Method of cleaning flues



1 March 29, 1949. T. J. PETERS METHOD OF CLEANING FLUES 2 Sheets-Sheet 1Filed June 25, 1946 FlEL-i- INVENTORZ i 75a ATTORNEY.

March 29, 1949. T, J. PETERS METHOD OF CLEANING FLUES 2 Sheets-Sheet 2Filed June 25, 1946 V INVENTORi 70M I P [TEE 5,

HIS ATTORNEY.

Patented Mar. 29, 1949 METHOD OF CLEANING FLUES Tom J. Peters, Chicago,111., wignor to Carnegie- Illinois Steel Corporation, a corporation ofNew Jersey Application June 25, 1946, Serial No. 879,108

2 Claims. (01.1344) 1 This invention relates to a method of cleaningflues. such method being particularly advantageous when employed in thecleanin of rectangular dues of relatively small cross section,

such as those in open hearth checkers and blast furnace stoves.

Among the objects of the invention is the provision of an improvedmethod of cleaning flues of the type described above, such method beingcharacterized bythe ease with which it is carried out and thethoroughness 'of cleaning effected thereby. I

These and further objects of the invention will be more readily apparentin the following description of preferred embodiments of the method andapparatus which are illustrated in connection with the cleaning of linesin open hearth furnace checker work. It is to be understood, however,that the invention is not restricted to the particular illustrativeexample, but that it may be used to advantage in the cleaning of varioustypes of fines, particularly flues of-relatively small cross section ofwhich the inner surface includes one or more relatively sharplongitudinally extendin corners.

Air for combustion in an open hearth furnace is preheated by passagethrough hot checker bricks. The products of combustion are drawn off thefurnace through checker bricks on the opposite side from the burnerbeing operated, such hot products of combustion yielding, their heat tothe checker bricks through which they pass on their way to the stack.The direction of the flow of the gas is periodically reversed, one setof checkers being cooled while the other is heated. It is inevitablethat the products of combustion carry with them fumes and finely dividedparticles of oxides and slags. and that such fumes and particlesgradually accumulate on the checker brick so that the checker openingseventually become coated therewith to such depth that the passage of gasis impeded. When such point of the operation of the furnace is reached,the furnace must be shut down and the checker work cleaned so as toremove such deposits from the flues of the checker work and to restorethe flues to their original cross section.

Heretofore the flues and checker work has been cleaned by laborers usinglong, handled scrapers and brushes which were inserted in and pushed orpulled through each flue. Such work is difficult and time consuming,requiring, on a 110 ton capacity open hearth furnace, approximately 84man hours with a lay-down period of the furnace of approximately 24.hours. Such method of cleaning is thus expensive, particularly becauseof the necessary relatively long period of inactivity of the furnace. Inaddition, it is not very effective, since the slag accumulations in theflues are hard and resist hand scraping and brushing.

, The present invention provides a power driven flue cleanin apparatusin which one or more flexible cleaning members, traveling. in an arcwhen free of contact with the flue, such are intersecting the surface ofthe flue, are caused initially to strike the flue surface with asubstantial impact and subsequently to travel thereover with a wipingaction. Such cleaning action preferably takes places in the vicinity ofthe one or more sharp longitudinally extending corners in the flue.-Such cleaning member thus cracks the accumulation of slag on the flue,by reason of its initial impact thereon, arid then removes it from theflue surface by its subsequent wiping action. The application of suchmember in the vicinity of the sharp corners, where the slag deposit isheaviest, is particularly advantageous since it was at such corner thatprevious flue cleaning methods were least effective.

The invention will be more readily understood by reference to theaccompanying drawings, in which:

Figure 1 is a view in side elevation of a preferred embodiment of acleaning head, portions of such head being shown in cross section, thesection being taken along the line I-I of Figure 2;

Figure 2 is a view in end elevation of the portion of the cleaning headshown in Figure 1 in the vicinity of the cleaning means;

Figure 3 is a view in end elevation of a modified cleaning means;

Figure 4 is a view partially in side elevation and partially in sectionof the cleaning means shown in Figure 3, the section being taken alongthe line IV -IV of Figure 3;

Figure 5 is a view in isometric projection of a checker work with thepreferred embodiment of the cleaning head inserted therein in operativeposition; and

Figure 6 is a schematic view showing the manner of operation of thepreferred cleaning means, such view being an end elevation taken from aplane containing the end wall 54, and in the direction toward thereader, in Figure 5.

A preferred embodiment of the cleaning apparatus is shown in Figures 1and 2. Such apparatus consists of a cleaning head having a casingconsisting of a main portion 2 housing a rotary air motor supplied withcompressed air through the flexible hose 6, the air supply beingcontrolled by the shut-off valve 4. When used in the preferred mannerthe cleaning head as a whole is lowered progressively through eachfluekeyed to shaft l and gear i8 being keyed to' shaft l4. The two outerends of transverse shaft l4 are provided with reduced outer ends 20which are threaded as shown to receive the disks 22 and the retainingnuts 24. The portions of shaft l4 between the further transverse housingportion l2 and the disks are protected by sleeves 26. In the embodimentshown in Figures 1 and 2 disks 22 are provided at the rim thereof with aplurality of short chains 28 spaced at equal angles around the disk. Thechains are chosen of such length, as will be apparent from aconsideration of Figures and 6, discussed below, that when the disks arerotating at suflicient speed to maintain the chains in a positionsubstantially radial of the disks, the outer ends of the chains, whenfree of contact with the flue, travel in an are which intersects thesides of the flue into which the cleaning head is introduced.

In a further modification of the apparatus, shown in Figures 3 and 4,relatively stiff but flexible brushelements are employed on the disksrather than chains. In this modification the brush element carryingdisks are designated 30, such disks being provided on their outer sideswith counterbores 32 to receive the retaining nut 24 and thus to allowthe disk closely to approach the flue end wall. Each disk 30 is providedwith a plurality of radially disposed brush elements 34 on the rim,elements 34 conveniently being stiff wire brushes. Each disk may furtherbe pro vided on its outer side with a plurality of equally spaced brushelements 36 extending parallel to the axis of the disk. Elements 36 may,as shown in Fig. 3, be spaced at varying radial distances on the disk inorder completely to cover the flue end wall.

A typical manner of use of the cleaning apparatus of the invention isshown in Figure 5, in which there is shown the upper surface of atypical open hearth checker work 38 made up of checker bricks 40 laid ina basket weave. In such checker construction the flues 42 extendvertically and are square in cross section. The cleaning head isinserted into a flue as shown and is progressively let down into theflue by paying out the hose 6. The apparatus is designed so that thelength of shaft I 4 is slightly smaller than the length of the fluedimension to which it is parallel. It will thus be seen that when themotor 2 is initiated and the disks 22 set in rapid rotation, the chains28 will be impelled outwardly by centrifugal force, in the portions oftheir travel wherein they are free from contact with the flue walls, andthat they will trike such walls in the vicinity of the opposed corners43. of the flue. In Figure 5 the opposed walls 48 and 50 are designatedside walls and the opposed walls 52 and 54 are designated end walls.

The manner in which the flexible cleaning members function to remove thedeposits 46 of slag and the like from the flue. particularly at thecorners will be somewhat clearer by consideration of Figure 6, in whichthe modification employing chains as the cleaning members isillustrated. It will be seen that but for the dis turbance in theirposition caused by contact with the flue walls, the chains 28, which inFigure 6 are shown traveling counterclockwise, tend" to occupy positionsradial of the disk and the outer ends thereof tend to travel-'in the areA when free of 'the flue walls. Initial contact between the outer end ofeach chain and flue wall is in the nature of a hammer blow, subsequentcontact between the chain and the flue wall in one traverse thereofbeing in the nature of a wiping contact. Such initial hammer blow andthe subsequent wiping or scraping of the flue wall by the outer endof-the chain cracks the slag accumulation and removes it from the fluein the vicinity of the portion contacted by the chain.

In some instances it is suflicient to pass the cleaning head through theflue in one angular position only relative to the flue since thecracking of the accumulation on one side of the corner of the flue tendsto loosen it in other positions, such as on the other wallat the otherside of the corner. It is preferred, however, particularly in view ofthe speed with which the operation is accomplished, where the flue is ofsuch dimension as to receive the cleaning head in two angularly spacedpositions, to employ a plurality of such. passes through the flue. Inthe case of the square flue illustrated in Figure 5, after one pass ofthe cleaning head in the angular disposition shown the head is withdrawnfrom the flue and reinserted in a position from that in the first passso that the ends of the chains then act upon the end walls 52 and 54 inlocations slightly inwardly of the corners.

' Use of the preferred embodiment of the flue cleaner shown in Figures 1and 2 has markedly reduced the amount of labor necessary to clean fluesin apparatus such as open hearth checkers and hot blast stoves. When thecheckers of the ton capacity furnace previously mentioned are cleaned bysuch apparatus. it is necessary to expend but seven man hours for thetotal operation. In addition, the overall furnace laydown time to allowsuch operation is but 8 hours as compared to the 24 hours previouslyrequired when the described hand cleaning methods were employed.

Having thus fully disclosed prefered embodiments of the method andapparatus for cleaning flues in accordance with the teaching of theinvention, I desire to claim as new the following:

1. A method of cleaning flues having two opposed longitudinal cornerscomprising progressively subjecting the flue longitudinally thereof intwo opposed locations in the vicinity of and on one side of saidcorners, to successive impacts followed by wiping contact by at leastone flexible member the outer end of which travels in an approximatelycircular are when free of contact with the flue, said are intersectingthe flue surfaces adjacent each of said opposed corners and lyingsubstantially in a plane containing the opposed flue corners, andrepeating the process above described with the flexible membercontacting the flue surfaces on the other side of each of the opposedcorners.

2. A method of cleaning a flue having a passage in the form of aparallelopiped and a rectangular cross section having opposed side andend walls comprising progressively subjecting Meant cent its corners, tosuccessive impacts iollowed two opposed side walls adjacent the otherend 10 wall of the flue, the outer end of each flexible member travelingin an approximately circular arc when tree 0! contact with the flue,laid arcs intersecting the opposed flue side walls and 1!-ingsubetantiallyinaplaneparalieltotheflue end walls, and repeating theprocess above described with the flexible members contacting the opposedend walls of the flue in the vicinity of the corners.

'rou ammo. a.

summons cum The following references are of record in the flle of thispatent:

UNITED STATES PATENTS Number Name Date 1,810,898 Fletcher July 10, 19291,796,458 Henchen Mar. 1'1, 1931 1,874,290 Aurand Aug. 30, 19321,917,388 McCarthy July 11, 1933 1,951,851 Turner Mar-.720, 19342,151,671 v Wright Mar. 21. 1939 A v roman rs'rm'rs Numher Country Date1 94.566 Great Britain 1909 8,117 Great Britain 1911 595,596. GermanyApr. 16, 1934 647,912 Germany Jul! 14, 193'! 857,991 Germany n-..- Mar.19, 1939

